Overview
EN ISO 19108:2005 (ISO 19108:2002) - Geographic information - Temporal schema - defines the conceptual model and common terminology for describing the temporal characteristics of geographic information. The standard focuses on temporal aspects as they are abstracted from the real world (emphasizing valid time rather than transaction time) and relies on existing information technology standards for temporal data interchange. It provides a foundation for representing temporal feature attributes, feature operations, feature associations, and temporal metadata in GIS and geospatial applications.
Key topics and requirements
- Conceptual temporal schema: a structure to represent time as part of geographic information, enabling consistent interpretation of temporal values.
- Geometry of time: modelling time as a dimension, including temporal objects, geometric primitives and temporal topology.
- Temporal reference systems: definitions for calendars, clocks, temporal coordinate systems and ordinal reference systems to ensure time values are unambiguous.
- Temporal position: representation of instants and intervals referenced to calendars/clocks or coordinate systems.
- Temporal feature components:
- Temporal feature attributes (e.g., validity intervals or recurring values)
- Temporal feature operations (behaviour or transformations over time)
- Temporal feature associations (linking features through time, succession)
- Temporal metadata: elements and metadata specifications for documenting temporal reference systems and dataset temporal characteristics.
- Conformance and interoperability: conformance classes and requirements for application schemas, data transfer, feature catalogues and metadata to support interoperable time-enabled data exchange.
- Test and guidance annexes: normative and informative annexes provide abstract test suites, guidance on using time in application schemas, and examples of calendar descriptions.
Applications and users
Practical uses include:
- Time-enabled GIS, spatio-temporal databases and temporal querying
- Change detection, historical mapping, time-series analysis, simulations and predictive modelling
- Tracking moving features (trajectories) and managing lifecycle information (validity intervals)
Primary users:
- GIS developers and software vendors
- Geospatial data modelers and systems integrators
- Metadata specialists, national mapping agencies and data custodians
- Researchers working with spatio-temporal analysis and simulations
Related standards
EN ISO 19108 is part of the ISO/TC 211 geographic information standards suite. It is intended to be used alongside spatial and metadata standards to provide comprehensive, interoperable descriptions of spatio-temporal datasets.
Keywords: ISO 19108, temporal schema, geographic information, time in GIS, temporal reference systems, temporal metadata, temporal feature attributes, spatio-temporal interoperability.
